Attorneys for former auto maker John Z. De Lorean said today that their client has passed a lie detector test showing that he did not enter intentionally into a $24 million cocaine-trafficking scheme as alleged by federal prosecutors.

The unexpected release of De Lorean's polygraph test results, conducted and attested to by a nationally recognized polygraph expert, marked the strongest evidence yet presented by the millionaire in his struggle to clear his name.

Although lie detector tests rarely are admitted as evidence in federal cases, the results are expected to complicate government efforts to convict De Lorean on the basis of testimony by James T. Hoffman, a convicted drug trafficker and government informer who says De Lorean asked to join a drug deal.

De Lorean attorneys Howard Weitzman, Donald Re and Mona Soo Hoo also disclosed for the first time what they said was secret grand-jury testimony by Hoffman alleging that De Lorean told him he had engaged in drug trafficking before and had helped start his Northern Ireland-based sports car company "through a drug transaction."

In the polygraph examination, according to a letter from University of Utah specialists David C. Raskin and Charles R. Honts, De Lorean denied that he had discussed drugs with Hoffman before 1982, denied that he proposed a drug transaction to Hoffman and said Hoffman proposed the drug deal.

The experts said indications of De Lorean's truthfulness from measurements of his breathing, skin condition, blood pressure, pulse and heart rate "were unusually strong and clear." He registered the maximum attainable score on a computer analysis of the results, they said.

De Lorean's attorneys have asked U.S. District Court Judge Robert M. Takasugi for permission to use the polygraph results in arguing for dismissal of the nine-count indictment against De Lorean on the grounds of "outrageous government conduct."

They said in their application filed here that the test results "show that De Lorean was set up, and that the government, and its agents, lied about it. The ramifications of these facts to this case, and to government narcotic prosecutions in general, are enormous."

Weitzman said he has been told that Hoffman has not taken a lie detector test. Hoffman has told prosecutors that De Lorean, once his neighbor in San Diego, met with him July 11, 1982, and said he "wanted to invest up to $2 million" in heroin to save his faltering company.

Unlike many other subsequent meetings between De Lorean and federal agents posing as drug traffickers and financiers, that initial meeting was not tape recorded because, official documents say, De Lorean was not the target of a federal investigation then.

Assistant U.S. Attorney James Walsh, chief federal prosecutor in the case, declined to comment on Hoffman's alleged statements to the grand jury or on the De Lorean polygraph test results. He noted, however, that "polygraph tests are not generally admissible as evidence in federal court."

Raskin, a psychology professor, said in a telephone interview that he tested De Lorean Saturday at his Salt Lake City laboratory.

In their letter, Raskin and Honts said De Lorean told them that Hoffman called him in June, 1982, "to offer his services to help De Lorean to arrange financing for his car company."

According to the letter, De Lorean said he did not think Hoffman would be much help but met with him several times until Sept. 4, 1982, when he said Hoffman first suggested a drug deal. De Lorean has said he then tried to end negotiations, but that Hoffman threatened his children's lives if he backed out.